Depends on what "speed" means and whether they actually need anything close to the current 52-11 top-end.

A couple years ago I had a friend who put together a 1x road drivetrain, 50T chainring and 11-32 cassette. He was badly bottomed-out on the hills. He didn't want to go to a wider-spaced cassette. I pointed out that his top several cogs were literally like-new sparkling clean, and that he was basically never putting power down at speeds above 30mph, so there'd be no problem with dropping the chainring down to at least the low 40s. He looked at me like I was crazy, and insisted that any big ring of less than 50T is obviously too small and "slow" for a road bike.
He did finally try the change a few months later. Unsurprisingly, he noticed no drawbacks.